Conventional wafer containers have two sections: a cover and a base. One such container is described in U.S. Pat. No. 6,237,771 (Haq). Haq discloses a cover and a base with receiving apertures. It is essential that the projections align with the receiving apertures to allow the container to be properly locked.
Once the projections align with the apertures, the two sections of the wafer container can be locked into place. If the top section is not properly aligned, the cover will have to be lifted and reinserted into the correct position. It is also difficult to observe in the Haq container whether the cover is engaging correctly to the base.
When a container is not properly locked it affects the stability of a stack of wafer containers. An improperly closed container may cause a stack of wafer containers to unnecessarily shift in position. It is also time consuming for an operator to remove covers from within a stack of containers to determine which container is responsible for the instability. Moreover, most wafer containers lack a gripping area that allows an operator to easily grip the cover for removal.
A need exists for a wafer container that has increased stability during stacking, a gripping area, and that is not constrained to specific angles when the top section (cover) engages to the base. A need also exists for a wafer container that allows an operator to easily observe if the two sections have correctly engaged to each other.